NoClassDefFoundError while running kafka connect for mongodb in standalone mode - mongodb

Question

I am trying to set up debezium connector with MongoDB in a standalone mode on my local machine by following this.
I have set up a replica set of MongoDB with 3 nodes, 1 master 2 replica (host = localhost, port = 27017, 27018, 27019) . I have started kafka and zookeper on the local machine as a quickstart guide.
After this, I downloaded the MongoDB connector plugin jar from here.
Set plugin.path variable to mongodb plugin jars as :
plugin.path=dbz_connector_mongodb_jar_path,KAFKA_HOME/libs
created connector config for standalone mode.
KAFKA_HOME/config/my_mongo_connector.properties :
{
"name": "my-mongo-connector",
"config": {
"connector.class": "io.debezium.connector.mongodb.MongoDbConnector",
"mongodb.hosts": "rc0/127.0.0.1:27017",
"mongodb.name": "myMongoConnceter",
"collection.include.list": "dbname.collectionName"
}
}
Now when I run kafka connect with below command :
cd KAFKA_HOME
bin/connect-standalone.sh config/connect-standalone.properties config/my_mongo_connector.properties
I see below error :
java.lang.NoClassDefFoundError: com/mongodb/MongoException
at java.base/java.lang.Class.getDeclaredConstructors0(Native Method)
at java.base/java.lang.Class.privateGetDeclaredConstructors(Class.java:3137)
at java.base/java.lang.Class.getConstructor0(Class.java:3342)
at java.base/java.lang.Class.newInstance(Class.java:556)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.versionFor(DelegatingClassLoader.java:392)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.getPluginDesc(DelegatingClassLoader.java:362)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.scanPluginPath(DelegatingClassLoader.java:334)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.scanUrlsAndAddPlugins(DelegatingClassLoader.java:268)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.registerPlugin(DelegatingClassLoader.java:260)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.initPluginLoader(DelegatingClassLoader.java:229)
at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.initLoaders(DelegatingClassLoader.java:206)
at org.apache.kafka.connect.runtime.isolation.Plugins.<init>(Plugins.java:61)
at org.apache.kafka.connect.cli.ConnectStandalone.main(ConnectStandalone.java:78)
Caused by: java.lang.ClassNotFoundException: com.mongodb.MongoException
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
at org.apache.kafka.connect.runtime.isolation.PluginClassLoader.loadClass(PluginClassLoader.java:104)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
... 13 more
Then I added mongo-java-driver-3.12.10.jar file to the kafka connect plugins folder which has this class com.mongodb.MongoException . But still, I face the same error.
I have also found that this jar is loading while running kafka connect command :
INFO Loading plugin from: debezium-connector-mongodb_path/mongo-java-driver-3.12.10.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:246)
INFO Registered loader: PluginClassLoader{pluginLocation=file:debezium-connector-mongodb_path/mongo-java-driver-3.12.10.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:269)
EDIT :
My problem of NoClassDefFoundError was solved by correcting plugin.path.
Earlier it was /opt/debezium-connector-mongodb and I changed it to /opt , as suggested in the comment.
My another mistake : I was taking connector propeties file in json format, so changed it into properties file format :
name:my-mongo-connector
connector.class:io.debezium.connector.mongodb.MongoDbConnector
mongodb.hosts=rc0/127.0.0.1:27017
mongodb.name=myMongoConnector
collection.include.list=dbname.collectionName
topic.creation.default.replication.factor=1
topic.creation.default.partitions=2
mongodb.members.auto.discover=false
Now kafka connect started but on insertion of new entry in mongo collection, kafka topic is not creating.
So now the problem is unable to create kafka topic even after data insertion in DB.